The subject of this thesis is food poisoning on cruise ships, symptoms, treatment and the water as a source of illness. In a broader sense, the term food poisoning includes all diseases that occur due to the consumption of unhealthy, spoiled or poisonous food, or food that contains harmful germs, bacteria, viruses or parasites. Poisoning occurs within 1-36 hours after consumption, and is manifested by the appearance of symptoms lasting from 1-7 days. There are several common symptoms of stomach virus and food poisoning: abdominal cramps, fever, cold sweat, nausea, diarrhea, loss of appetite, muscle and joint pain, headache and vomiting. However, in food poisoning, symptoms appear within a few hours of exposure to the infection, while in gastric virus they occur after 24 to 48 hours. Milder cases of food poisoning usually resolve on their own after a few days. Until then dehydration should be prevented and solid foods and dairy products avoided. In addition to food, it is important to mention water as a source of infection. Improper water management could lead to epidemics of infectious diseases or poisoning by various chemicals. Since large amounts of food are processed and consumed on cruise ships, the chances of an outbreak are high. For this reason, it is necessary to pay special attention to the purchase of food (shelf life, quality, source..), proper storage, keeping and hygienic standards of staff in contact with food. According to international regulations cruise ships must have a doctor on board as well as passenger ships that have more than 12 passengers. In case of suspected food poisoning, if there is no doctor on board it is advisable to seek radio medical advice.